The present disclosure is directed toward a multiple pass operation for use with an image forming apparatus. More particularly, the operation includes a system for providing a select number of passes of a media sheet through the image forming apparatus for rendering a layer of clear toner on the media sheet.
A use of clear toner on printed media sheets is becoming more diverse with newly discovered applications for using the clear toner as a way to achieve particular visible effects. For example, a layer of clear toner may provide the media sheet with a glossy appearance, or it may provide a textured image, that is supported on the media sheet, with a perceived third dimension. One aspect of using clear toner is an ability to produce certain effects while requiring less expensive manufacturing methods and substrate materials. As mentioned, texture is a desired visual effect that may be achieved using clear toner. For example, the use of clear toner on a generally uniform surface may provide the appearance of a third dimension when the toner (i.e., forming the image) is viewed relative to a blank region of the print media sheet. The reflective behavior of the clear toner may further contribute to the degree of the perceived dimension based on a reflection at select viewing angles. To further achieve a perceived textured surface having a noticeable tactile feel to a touch, the media sheet may be subjected to multiple passes through the image forming apparatus for building a clear toner layer having a certain pile height. Each pass may be used to render one coat of the clear toner layer. However, media sheet-degradation is associated with a conventional operation after a certain number of passes. The media sheet generally degrades as it is moved through a paper path. The media sheet may get caught in the paper path if the pile height of the clear toner layer is built too high. Accordingly, the caught media sheet may cause a jam to the image forming apparatus. The jam may decrease a production efficiency of the image forming apparatus if additional, queued print jobs are held until the jam is remedied and the apparatus is made operative again.
Another problem associated with a conventional operation is an increased risk of the toner particles not fully melting onto the print media sheet after a certain number of passes. The toner particles that fail to adhere to the underlying clear coat may deposit on stations of the image forming apparatus when the print media sheet returns for another pass. If the image forming apparatus continues to operate under this condition, there increases a risk of damaging stations of the apparatus. This damage can lead in a long term to image quality defects and more permanent mechanical problems.
There is thus a need for a system that provides a more visible layer of clear toner while reducing a risk of jamming the image forming apparatus.